The 1960s ushered in a new era in U.S. demographic history characterized by significantly lower fertility rates and smaller family sizes. What catalyzed these changes remains a matter of considerable debate. This paper exploits idiosyncratic variation in the language of Comstock statutes, enacted in the late 1800s, to quantify the role of the birth control pill in the 1960s. Almost fifty years after it appeared on the U.S. market, this analysis provides new evidence that oral contraception accelerated the post-1960 decline in marital fertility.